Stormwater runoff occurs when stormwater generated from precipitation or melting events contacts a surface impervious to liquids, such as paved roadways, or when an absorbent surface becomes fully saturated. Unless diverted or drained, excess stormwater runoff buildup on such impervious surfaces can lead to severe flooding. To guard against flooding due to stormwater runoff, storm sewers have long been used to drain and subsequently divert stormwater runoff. Generally, storm sewers comprise a drainage structure that serves as the entryway for stormwater runoff to enter the storm sewer and a piping or channeling system attached thereto that subsequently transports the stormwater runoff from the drainage structure to a water body such as a canal, river, lake, reservoir, sea, ocean, etc. Drainage structures often receive stormwater runoff through either a horizontal inlet, such as with roadway drains, or a vertical inlet, such as with curbside drains. To separate out debris and contaminants from the stormwater runoff, inlet grates configured to rest upon or cover the inlet of the drainage structure are often used. Such inlet grates typically have a series of openings disposed therein that serve to prevent debris exceeding the diameter of the grate openings from entering the drainage structure. However, inlet grates typically used within the art often prove largely insufficient during periods of heavy stormwater runoff and are burdensome when access to the cavity of the drainage structure is needed.
Typically, inlet grates are manufactured to rest over the inlet of the drainage structure such that the stormwater runoff must first contact or pass through the grate before entering the cavity of the drainage structure. Accordingly, debris blockaded by the inlet grate will often either remain on the grate or be propelled off of the grate due to the force of the inflowing stormwater runoff. Both outcomes are problematic. If the debris remains on the grate, the debris may clog the openings of the grate, thereby impeding the flow and ultimately reducing the volume of stormwater runoff that may enter the drainage structure. If debris is propelled off of the grate, the debris effectively litters the environment surrounding the drainage structure. Moreover, because conventional inlet grates are generally manufactured as a unitary piece of cast iron they are often extremely heavy and cannot be disassembled. Accordingly, to access the bottom of the drainage structure and/or the piping or channel system attached thereto, an individual or machine must initially lift the heavy grate from the inlet to gain access and subsequently place the grate back on the inlet to reseal the drainage structure. Thus, due to the weight of the inlet grate, a great deal of strenuous force must be exerted to remove and subsequently replace the inlet grate which can potentially injure the individual or damage the machine carrying out such actions.
Accordingly, a need exists in the art for a filtration apparatus and method for use with drainage structures that captures debris from stormwater runoff without impeding or reducing the volume of stormwater runoff that may enter the drainage structure. Moreover, there is a need in the art for a filtration apparatus for use with drainage structures that can be easily manipulated to provide simple access to the bottom of the drainage structure.